The subthreshold swing is a feature of a transistor's current-voltage characteristic. In the subthreshold region the drain current behavior is similar to the exponentially increasing current of a forward biased diode. A plot of logarithmic drain current versus gate voltage with drain, source, and bulk voltages fixed will exhibit approximately logarithmic linear behavior in this MOSFET operating region. To improve the subthreshold properties, a negative capacitance field effect transistor (NC-FET) using a ferroelectric material has been proposed. However, the negative capacitance may cause a hysteresis.